Filament for incandescent lamps.



F. G. KEYES.

FILAMENT FOR INCANDESCENT LAMPS.

APPLICATION FILED FEB. l7 I915- Patented Dec. 14, 1915.

WITNESSES FREDERICK G. REYES, OF EAST ORANGE, NEW JERSEY.

FILAMENT FOR INCANDESCENT LAMPS.

Specification of Letters Patent.

Patented Dec. 11, 1915..

Application filed February 17, 1915. Serial No. 8,747.

To all whom it may concern:

Be it known that l, FREDERICK G. KEYns, a citizen of the United States, and resident of East Orange, county of Essex, State of New Jersey, have invented certain new and useful Improvements in Filaments for Incandescent Lamps, of which the following is a specification.

The present invention has to do more particularly with metallic filaments, generally of tungsten, such as I have made use of in practice and such as are covered by various applications of mine for Letters Patent of the United States,as, for example, my applications Numbers 811,002 and 811,003, filed January 8th, 1914. The filaments described in the said applications are rather heavy filaments of tungsten and in the present instance I provide a filament having the same characteristic of current carrying capacity produced, however, by somewhat difierent means. For example, in the present instance, the terminals of the filament are or may be conductors of ordinary size of diameter, whereas, a greater diameter is given to the body of the filament by winding closely around the original filament a helix of wire of tungsten or some highl resisting metal. In this way, a greater radiating surface is secured and a concentration of the light effects is also obtained.

The invention is illustrated in the accompanying drawings, in which- Figure 1 is a vertical section through the major portion of a lamp embodying my invention; Fig. 2 is a detail view of one embodiment of my invention, and Fig. 3 illustrates a modification.

In the first figure of the drawings, 1 is a lamp lobe and 2 a reduced extension thereof. ithin a reentrant portion 3 of the extension are mounted seals 4-, 4, within which are wires 51, 51, soldered or otherwise connected to lead rods or wires 5, 5, with interposed spirals 6, 6, for preventing the application of too much strain directly to the seals. The lead wires, 5, 5, pass through a disk 7 of some suitable material such as aluminum, being insulated therefrom by sleeves 8, 8, and extending downward below the disk and being connected at the bottom by screw connections or otherwise with metallic blocks or plates 9, 9. The disk 7 is supported upon a shoulder 10 extending around the interior of the tubular ortion 2 near-the mouth thereof and the said disk also supports wires 11, 11, which at their lower ends support the filament at various points to prevent too great sagging.

The filament itself, shown at 12, consists of a wire of tungsten or other hlghly refractory material, which wire is generally surrounded by a coil or spiral of the same material in the form of a closed helix. This arrangement supplies a large radiating surface and a concentrated light effect.

At the lower ends of the leads, 5, 5, are blocks 9, 9, preferably of iron, the same being perforated at 14, 14, as shown in dotted lines. Into these perforations may be pressed plugs or tapering pins 15, 15, of molybdenum, tungsten or like metals. Each of the tapering pins 15, 15, is wound with a coil or spiral of bare wire, generally tungsten wire, the same being one of the ends of the filament 12. In this way a good electrical connection is made between the terminals of the filament and the support 9, 9.

While the wires 11, 11, accomplish to a great extent the purpose of preventing too great sagging on the filament, yet, between the different supports there might come a touching of the different coils of the filament if the structure of the filament as a whole were a simple series of coils. The presence of the wire at the center of the filament relieves any tendency to making of contact between separate coils and is, therefore, of advantage as supplementing the wires 11, 11.

I claim as my invention:

A filament for incandescent lamps consisting of a straight wire of tungsten or other refractory material and a helix of similar material intimately surrounding the said wire.

Signed at New York in the county of New York and State of New York this 16th day of February, A. D. 1915.

FREDERICK G. KEYES.

Witnesses:

GEORGE H. Srocxnnmen, Tnos. H. BROWN. 

